Process for treating hydrocarbons



' March 13,1934.

E. A. BOSING 1,951,324

PROCESS FOR TREATING HYDROCARBONS Filed Aug. 28, 1950 Ill: Ernest Aulao six ag sodium hydroxide to the liter.

It is thought that the chemical constituents of this solution, doctor solution, react with the sulfur derivatives, possibly mercaptans, to produce a lead derivative of those substances. A general lzed chemical equation of the reaction is given according to the following scheme, where R is a hydrocarbon radical.

The resultant chemical reaction, therefore, produces lead derivatives of the sulfur impurities which remain dissolved in the hydrocarbon and as a by-product, forms an aqueous solution of sodium hydroxide, immiscible with the hydrocarbon. The rate of flow through the reaction chamber, and therefore the time of contact of the distillate with the sulfur combining reagent is so regulated that substantially all of the sulfur derivatives unite to form the sulfur-metal compounds or lead mercaptides. These sulfur-metal compounds are brightly colored, and impart a color to the hydrocarbon which is known as eanary yellow.

The method of proportioning the quantities of distillate and sulfur combiningreagent is regulated at the entrance point 13 of the reagent. This particular flow-regulating device is of con ventional design andmay comprise metered and calibrated orifices permitting a regulated flow of predetermined quantities of the fluids to be mixed, which quantities are determinable knowing the amount of sulfur in the hydrocarbon and knowing the strength of the sulfur combining reagent. An emcient mixing of the fluids is obtained by forcing them through a multiplicity of small openings or through a star-shaped diaphragm or other well known device for that purpose.

After the completion of the-reaction in the reaction chamber 11, the mixed products are urged into a separator it where the treated distillate disengages itself from the water solution of sodium hydroxide so produced and floats upon the surface of the sodium hydroxide. The separated distillate is then removed from the separator container 14 to suitable storage tanks 15 for further treatment, while the solution of sodium hydroxide is drawnoff and carried to a suitable mixing tank for the production of reagents, as will be described more in detail hereinafter.

-The treated distillate containing insolution certain metal derivatives of the sulfur impurities, for instance lead mercaptide,

as the reaction chamber 11 mentioned hereinabov'e'gafter removal of excess alkali by means of a water wash if required.

At this point in the procedure, I am able to effectively eliminate substantially all the metallic constituents in the distillate as insoluble oxygen derivatives, which derivatives are subsequently ripeness removed, united with the sodium hydroxide produced in reaction chamber 11 from the treatment with the sulfur combining reagent, thus forming an additional quantity of the reagent which may thereafter be used for treatment of additional quantities of sour distillate. At the same time, the sulfur derivatives are changed to materials which do not impart a bad color or offensive odor to the hydrocarbon or petroleum fraction.

The treatment which I use consists in adding to the distillate containing the colored sulfurmetal derivatives, a solution of an oxygen pro-- ducing substance, such as a peroxide. Although any peroxide can be used, I have found that hydrogen peroxide is more readily adapted for the purpose than other peroxides, and I add a dilute solution of hydrogen peroxide to the distillate containing the mercaptide whereby the hydrogen peroxide is caused to combine with these merc'aptides with the formation of a disulphide, soluble in the distillate, and a metal oxide insoluble in the distillate. The checal reaction may be shown as follows:

The hydrogen peroxide is added to the stream of hydrocarbon or petroleum fraction either at some point prior to its entrance to the reaction chamber 16, or added directly to the reaction chamber, and the quantities of dilute hydrogen peroxide and the distillate so proportioned that all oi the mercaptidemust change to disulphide and metallic oxide. The amount of hydrogen peroxide required to efiect this desirable change will, of necessity, vary with the composition of the distillate treated. I have found that when treating certain fractions obtained from California crudes which are extremely sour, I have been able to produce a sweet distillate by using one per cent by volume of one hundred volume hydrogen peroxide suitably diluted with water.

I have been able to obtain good results by agitating a given volume of distillate with about one third its volume of extremely dilute aqueous peroxide solution. In one case, one drop of thirty per cent hydrogen peroxide to 33 cc. was used effectively to sweeten lilo cc. of distillate. Slightly elevated temperatures aid my process, as I have greatly facilitated the process at ti) to 40 C. a

After the completion of the reaction between the hydrogen peroxide an the lead mercaptides has occurred in the reaction chamber 18, which may be shown by the fact that the hydrocarbon has acquired a good water white color and that additional hydrogen peroxide causes no additional formation of metallic oxide, insoluble in the distillate, the purified and sweet distillate is urged to the separator 17 where the watery sludge of lead oxide 18 is precipitated from the treated and sweetened fraction.

The hydrogen peroxide used for, this treatment may be either a hydrogen peroxide of high strength, such as one hundred volume, or thirty per cent hydrogen peroxide, or a more dilute solution, when it is desired to effect a washing action as well as a chemical oxide action in the reaction chamber or turbulence coil'16 and separator 17. For this purpose, the concentrated hydrogen peroxide is obtained from a central storage 19 and diluted to any suitable degree in a dilution tank lid 20, such dilution varying with the treatment desired, although in most cases, being to three per cent hydrogen peroxide or ten volume hydrogen peroxide. This aqueous solution of hydrogen peroxide being oi the desired reacting strength is mixed with the distillate carrying the mercaptide at the point 21, which mixture point may be either in the reaction chamber proper or immediately prior to the entrance of the distillate to the reaction chamber.

The separator tank 17 has a suitable bleeder line 21 attached thereto by means of which excess water is removed from the tank and taken to waste, or which may be used thereafter in the process. The lead oxide formed as a sludge by the reaction of hydrogen peroxide upon the lead mercaptides, is drawn from the separator 17 and led to a solution mixing tank 22, while the sweetened distillate is siphoned from the separator 17 and subjected to a subsequent washing, or if sufliciently freed from water soluble impurities, led immediately to a storage tank 23 for subsequent The solution mixing tank 22, made of any suitable design and of materials which will effectively withstand the corrosive action of caustic soda, or other caustic alkali, is provided with an agitator 24 whereby the metallic oxide sludge from the separator 17 and aqueous solutions of caustic alkali from the separator 14 are mixed and caused to unite chemically to form additional solutions of sulfur combining reagent. Theoretically, suflicient quantity of sodium hydroxide is produced in this reaction to completely react with the oxide to form the sodium plumbite. In practice, however, I have found that insumcient amounts of sodium hydroxide are produced due to uncontrollable losses in the process, and therefore, have found it necessary to add a small amount of strong caustic alkali to completely change the oxide sludge to water soluble sodium plumbite and to produce in this solution the requisite alkalinity.

The solution so produced in the mixing tank 22 is thereafter caused to flow by means of the pump 25 to the storage tar'ik 26 where it'is ready for use in treatment of additional amounts of sour distillate.

It is thus seen that my process provides an economic cyclic treatment of sour distillates whereby the malodorous compounds, usually mercaptans, are changed to inoffensive disulphides which produce no bad color, or impart no disagreeable odor to the finished distillate. Since the hydrogen peroxide treatment has efiectively eliminated all the lead added to the distillate, no color producing lead sulfur compound remains in the distillate, and since it is these compounds which gradually change on standing in air and sun-light to colored derivatives, distillates so treated by my method do not re-acquire an of! color, nor do they gradually assume a bad odor with passage of time, but remain sweet and of good color.

It is therefore unnecessary to treat distillates produced by my method with treated clay in order to insure a water white distillate.

What is claimed is: I

1. The cyclic process of treating sour petroleum distillates containing sulfur which comprises treating the distillate with an alkaline aqueous solution of a sulfur combining substance containing lead, separating the treated distillate from the alkaline aqueous residue, treating the recovered distillate with an aqueous solution of hydrogen peroxide suiiicient to form an insoluble oxygen compound of lead with the lead compounds in the distillate, separating the insoluble oxygen compound of lead from the sweetened distillate, and thereafter producing an alkaline aqueous solution of the sulfur combining substance by interaction of said insoluble compound and said residue for. recirculation in the system.

2. The cyclic process of treating sour petroleum distillates containing sulfur which comprises treating the distillate with an aqueous solution of a plumbite whereby lead derivatives of substantially all the sulfur compounds are produced, separating the treated distillate from the alkaline aqueous residue, treating the recovered distillate with an aqueous solution of a peroxide to'form an insoluble oxygen derivative of lead with the lead compounds in the distillate, separating the insoluble oxygen compound of lead from the .sweetened distillate, and thereafter producing an alkaline solution of a plumbite by the interaction of said insoluble compound and said residue for recirculation in the system.

3.. The process of treating sour petroleum distillates which comprises treating the distillate with an alkaline aqueous solution of a lead compound, separating the treated distillate from the alkaline aqueous residue, treating the recovered distillate at a slightly elevated temperature with a very dilute aqueous solution of hydrogen peroxide sufiicient to form an insoluble oxygen compound of the lead contained in the distillate, and thereafter separating the oxygen compound of lead from the sweetened distillate.

4. The process of treating'sour petroleum distillates containing sulphur which comprises treating the distillate with an aqueous solution of a plumbite whereby lead derivatives of substantially all the sulphur compounds are produced, separating the treated distillate from the aqueous alkaline residue, treating the recovered distillate with an aqueous solution of a peroxide to form an insoluble oxygen derivative of lead with the lead compounds in the distillate, and separating the insoluble oxygen compound of lead from the treated distillate. ERNEST A. BOSING. 

